In Patent Document 1, as illustrated in FIG. 3, ribs 36b, 36c formed on an inner wall of an exterior case 3a of an electric motor 5 constitute an oil guide for picking up and guiding oil, and openings 37a, 37b are formed in a ring-shaped flange portion 29. Thus, the ribs 36b, 36c function as the oil guide, and the oil guided by the ribs 36b, 36c are introduced into a space portion C from the openings 37a, 37b (paragraph 0029).
In addition, in Patent Document 1, as illustrated in FIG. 4, a boss 41 for a bearing 22 which supports a shaft 20 is formed, and an upper portion of the boss 41 is partly cut out to form an opening 41a for introducing the oil. An inside of the boss 41 forms an oil pool D in collaboration with an end surface of the shaft 20. The oil pool is formed to be relatively small for the purpose of introducing the oil quickly to a lubricating hole 43 formed in the shaft 20. At a lower portion of the oil pool, the wall of the case comes close to the inner race of the bearing so as to prevent the oil from escaping from the bearing 22 (paragraph 0031). This structure can introduce the oil the oil pool D by causing the oil to fall onto two ribs 46 formed in a radially-outer portion of an inner case 3b, and then dropping the oil to introducing ribs 42 (paragraph 0032).